SDK 2.1.0: clang 19.1.1 picolibc_interface compile error

[geurtv]

pico-sdk 2.1.0 compiles fine with clang 18.1.3 (LVM-ET-Arm-18.1.3) but with clang 19.1.1 (LLVM-ET-Arm-19.1.1) I get the following compile error:

pico-sdk/2.1.0/src/rp2_common/pico_clib_interface/picolibc_interface.c:102:83: error: use of undeclared identifier 'CLOCKS_PER_SEC'
  102 |     tms->tms_utime = (clock_t)(to_us_since_boot(get_absolute_time()) / (1000000 / CLOCKS_PER_SEC));
      |                                                                                   ^

I don't know what a correct fix is. For example, if I add the following code to picolibc_interface.c:

#include <time.h>

It compiles and CLOCKS_PER_SEC == 1000000.

clang 18's time.h includes machine/time.h, clang 19's does not. So if instead I add:

#include <machine/time.h>
#include <time.h>

It again compiles, but now CLOCKS_PER_SEC == 100 (same as clang 18).

[lurch]

I've not used clang myself, but is https://github.com/raspberrypi/pico-sdk/blob/master/src/rp2_common/pico_clib_interface/include/llvm_libc/sys/times.h#L12 relevant here?

[geurtv]

I assume llvm_libc/sys/times.h will only be included for clang+llvm_libc (and not clang+picolibc), but I guess it does indicate the value for CLOCKS_PER_SEC is expected to be 100. So that leaves the question what the correct include is to get CLOCKS_PER_SEC == 100 in picolibc_interface.c.